Integral image elements which use a lenticular lens sheet or a fly's eye lens sheet, and a three-dimensional integral image aligned with the sheet, so that a user can view the three-dimensional image without any special glasses or other equipment, are known. Such imaging elements and their construction, are described in "Three-Dimensional Imaging Techniques" by Takanori Okoshi, Academic Press, Inc., New York, 1976. Integral image elements having a lenticular lens sheet (that is, a sheet with a plurality of adjacent, parallel, elongated, and partially cylindrical lenses) are also described in the following Unites States patents: U.S. Pat. No. 5,391,254; U.S. Pat. No. 5,424,533; U.S. Pat. No. 5,241,608; U.S. Pat. No. 5,455,689; U.S. Pat. No. 5,276,478; U.S. Pat. No. 5,391,254; U.S. Pat. No. 5,424,533 and others; as well as allowed U.S. Pat. No. 5,543,964. Lenticular image elements are therefore considered a special case of the broader integral image element class.
Integral image elements using reflective layers behind the integral image to enhance viewing of the integral image by reflected light, are also described in U.S. Pat. No. 3,751,258, U.S. Pat. No. 2,500,511, U.S. Pat. No. 2,039,648, U.S. Pat. No. 1,918,705 and GB 492,186. While various types of reflecting layers are described in the foregoing, none of those references attaches any particular importance to the characteristics of the reflective layer nor suggests how such characteristics might affect image quality seen by a viewer.
Integral image elements with lenticular lens sheets use interlaced vertical image slices which, in the case of a three-dimensional integral image, are aligned with the lenticules so that a three-dimensional image is viewable when the lenticules are vertically oriented with respect to a viewer's eyes. Similar integral image elements, such as described in U.S. Pat. No. 3,268,238 and U.S. Pat. No. 3,538,632, can be used to convey a number of individual two-dimensional scenes (such as unrelated scenes or a sequence of scenes depicting motion) rather than one or more three-dimensional images. However, the appearance of animated images with an apparent look-around ability, has been suggested in U.S. Pat. No. 5,543,964. In practice, when smaller sized versions of such images are manufactured, they are often produced with many copies of the same integral image on one sheet, the individual images being later cut apart for use.
An inherent limitation with animated lenticular images, such as those of No. 3,268,238, U.S. Pat. No. 3,538,632, or suggested by U.S. Pat. No. 5,543,964, is that the range of animation that can be captured, or its detail, is necessarily limited. In particular, where it is desired to record an animation sequence with "n" views, this means that lines from those "n" views must be interleaved such that there are at least "n" image lines (sometimes referenced as image strips) under each lenticule. The lines must have some finite width which is limited to the resolution of the printer used to print them, and the lenticular lenses have limited resolving power. Therefore, "n" is an integer which is necessarily limited for any given size lenticular image element. With current technology, "n" can allow up to about 25 views under a lenticule for an image intended to be viewed a few inches or a few feet away. However, even if technology might improve this number, it will always be desirable to have a way of capturing on a lenticular image, even more views. In this way, even longer motion sequences could be captured and displayed, or even more detail of a particular range of motion could be displayed.